Apparatus and method for detecting the presence of an agent

Abstract

An apparatus and method for detecting an agent utilizes a substrate, a waveguide on the substrate, a light source, a photo-detector, an optical coupler on the substrate, and a processor. The light source is configured to emit light into the waveguide. The photo-detector is configured to detect light. The optical coupler is configured to direct a first portion of light propagating from the waveguide towards the photo-detector and to direct a second portion of the light propagating from the waveguide back into the waveguide. The waveguide and the optical coupler at least partially form a resonator. A substance is at least one of embedded within the waveguide and adjacent to the waveguide. The substance is reactive to the agent. The processor detects a change in a resonance lineshape of the resonator caused by the reaction of the substance to the agent.

1 . An apparatus for detecting an agent comprising:
 a substrate;   a waveguide on the substrate;   a light source coupled to the waveguide and configured to emit light into the waveguide;   a photo-detector coupled to the waveguide and configured to detect light;   an optical coupler on the substrate and configured to direct a first portion of light propagating from the waveguide towards the photo-detector and to direct a second portion of the light propagating from the waveguide into a second waveguide, the second waveguide and the optical coupler forming a resonator;   a substance being at least one of embedded within the waveguide and adjacent to the waveguide, the substance being reactive to the agent; and   a processor in operable communication with the photo-detector to detect a change in a resonance lineshape of the resonator caused by said reaction of the substance to the agent.   
     
     
         2 . The apparatus of  claim 1 , further comprising a material adjacent to the waveguide, and wherein the substance is embedded within the material 
     
     
         3 . The apparatus of  claim 2 , wherein the substance is embedded within the waveguide. 
     
     
         4 . The apparatus of  claim 1 , wherein said detection of the change in resonance lineshape comprises detection of a change in at least one of the free spectral range (FSR) of the resonator and the Finesse of the resonator. 
     
     
         5 . The apparatus of  claim 4 , wherein the substrate comprises a silicon layer and the waveguide is at least partially formed within the silicon layer. 
     
     
         6 . The apparatus of  claim 5 , wherein the silicon layer comprises a plurality of holes therein forming a photonic crystal arrangement to create at least a portion of the waveguide. 
     
     
         7 . The apparatus of  claim 6 , wherein the agent is at least one of a biological agent a, a chemical agent, and a biochemical agent. 
     
     
         8 . The apparatus of  claim 7 , wherein the waveguide has first and second opposing ends, the light emitted by the light source entering the first end of the waveguide and propagating from the second end of the waveguide, and the photo-detector is arranged to capture the light that propagates from the second end of the waveguide and generate a signal representative thereof. 
     
     
         9 . The apparatus of  claim 8 , wherein the resonator is a linear resonator. 
     
     
         10 . The apparatus of  claim 8 , wherein the resonator is a ring resonator and further comprising a second photo-detector arranged to capture light propagating from the first end of the resonator, and wherein the processor is further configured to compare the respective signals generated by the photo-detector and the second photo-detector. 
     
     
         11 . An apparatus for detecting an agent comprising:
 a substrate;   a waveguide having first and second opposing ends on the substrate;   a light source on the substrate being operable to emit light into the waveguide;   first and second photo-detectors on the substrate being arranged to capture light and configured to generate a signal representative thereof;   first and second optical couplers on the substrate, the first optical coupler being arranged to direct at least some of the light propagating from the first end of the waveguide towards the first photo-detector and direct at least some of the light propagating from the first end of the waveguide back into the waveguide, the second optical coupler being arranged to direct at least some of the light propagating from the second end of the waveguide towards the second photo-detector and direct at least some of the light propagating from the second end of the waveguide back into the waveguide, the waveguide and the first and second optical couplers at least partially forming a resonator;   a material being at least one of embedded within and adjacent to at least a portion of the waveguide having a substance embedded therein, the substance being reactive to the agent, wherein the agent is one of a biological, chemical, and biochemical agent; and   a processor on the substrate and in operable communication with the first and second photo-detectors and configured to detect a change in a resonance lineshape of the resonator caused by said reaction of the substance to the agent.   
     
     
         12 . The apparatus of  claim 11 , wherein the resonator is a linear resonator and the first and second optical couplers each comprise a reflective surface. 
     
     
         13 . The apparatus of  claim 11 , wherein the resonator is a ring resonator and the first and second optical couplers are evanescent couplers. 
     
     
         14 . The apparatus of  claim 13 , wherein said detection of the change in resonance lineshape comprises detection of a change in at least one of the free spectral range (FSR) of the resonator and the Finesse of the resonator. 
     
     
         15 . The apparatus of  claim 14 , wherein the substrate comprises a silicon layer, the waveguide is at least partially formed within the silicon layer, and the light source is formed on the substrate. 
     
     
         16 . A method for detecting an agent comprising:
 forming a waveguide having first and second opposing ends on a substrate;   positioning a substance at least one of within the waveguide and adjacent to the waveguide, the substance being reactive to the agent;   directing light into the first end of the waveguide, the light propagating through the waveguide and from the second end thereof;   directing a first portion of the light propagating from the second end of the waveguide back into the waveguide to be emitted from the first end thereof;   capturing a second portion of the light propagating from the second end of the waveguide;   directing a first portion of the light propagating from the first end of the waveguide back into the waveguide towards the second end thereof, the waveguide at least partially forming a resonator;   capturing a second portion of the light propagating from the first end of the waveguide; and   generating a signal representative of a change in a resonance lineshape of the resonator caused by said reaction of the substance to the agent.   
     
     
         17 . The method of  claim 16 , wherein the resonator is at least one of a linear resonator and a ring resonator. 
     
     
         18 . The method of  claim 17 , wherein said change in resonance lineshape comprises detection of a change in at least one of the free spectral range (FSR) of the resonator and the Finesse of the resonator. 
     
     
         19 . The method of  claim 18 , wherein the substrate comprises a silicon layer, the waveguide is at least partially formed within the silicon layer, and the silicon layer comprises at least one of a doped region and a plurality of holes therein forming a photonic crystal arrangement to create at least a portion of the waveguide. 
     
     
         20 . The method of  claim 19 , wherein the material is a permeable polymer-based material formed over the silicon layer.